I am reading a technical paper and I don't quite understand some statistical terms such as:
- ..."Although the asymptotic mean of $z(\phi)$ is zero, it is possible for the score statistic derived by this theory to have means of order $O(n_{ij}^{-1/2})$"... what does $O(n_{ij}^{-1/2})$ means here?
- ...$E[z(\phi)]=O(n_{0}^{-3/2},n_{1}^{-3/2})$, that is the bias to order $O(n_{0}^{-1/2},n_{1}^{-1/2})$ is zero. What does the $O(n_{0}^{-1/2},n_{1}^{-1/2})$ mean?
Where $z(\phi)$ is the z-score from standard normal distribution in terms of $\phi$ and $n$ is sample sizes in integers.
